These days, Sasami has taken to visiting Tenchi’s aunt, and she especially likes to see Tenchi’s newest cousin (his aunt’s grandson), baby Taro. Tenchi himself wouldn’t mind having his aunt and the baby over to visit sometimes, although looking after Taro for a few days probably wasn’t what he had in mind.
With Taro’s mother ill, Tenchi is asked to baby-sit- and with all the girls in the house, Tenchi’s aunt is sure it won’t be too difficult for him. Indeed, Ryoko, Ayeka and Mihoshi are all quick to fuss over the small visitor, but looking after him is another matter entirely. The problems begin whilst Ryoko and Ayeka are fighting over him; Taro decides that it is time to relieve himself, and Ryoko is quick to disappear whilst the baby pees all over Ayeka.
Not put off by this early setback, the girls decide to help change him. Ayeka offer to wash Taro’s diaper, whilst Mihoshi attempts to put a new one on. Unfortunately, even with a How-To guide, she can’t tie up the cloth correctly, and ends up bandaging up the baby’s entire lower body!
Returning, Ryoko decides that she will help out too- by making up a bottle of milk for Taro. However, as Tenchi soon discovers, although Ryoko managed to give Taro the powdered formula meant for him, she also forgot to add water. And even Mihoshi’s success in finally putting the diaper cover on ends up counting for little when Taro pees again straightaway.
Within a few hours, there are a whole stack of diapers out drying on an impromptu washing line set up between Azaka and Kamidake- not the noblest duty ever undertaken by a Jurai guardian. Still reasonably enthusiastic, the girls continue their attempts to look after Taro. Ryoko takes him flying on her back (at least until he starts pulling her hair) and Ayeka unsuccessfully tries to feed him some baby food. Mihoshi, however, has had enough- and when the baby starts crying, so does she.
The day continues in an endless round of milk bottles, diapers, and fighting over who gets to do what, until finally Tenchi decides to take a short break in the outdoor bath. Even that proves to be fraught, however- before he can climb out, Mihoshi and Taro come in for a dip. Feeling awkward, Tenchi hides away under the water, and ends up passing out from the heat.
Whilst Sasami revives Tenchi and cools him off, Ryoko, Ayeka and Mihoshi continue their work, by now preparing milk and changing diapers as if on autopilot. By the evening, everyone is exhausted, and when Taro cries, Ryoko automatically changes his diaper once more before falling back to sleep. Unable to awaken her, Taro decides to crawl off elsewhere in search of attention, and ends up going to Washu’s lab.
Hard at work, Washu at first does not see this new visitor, at least until he starts pulling her hair. Having been in the lab all day, Washu didn’t even know that the baby was at the house, but when she sees everyone else asleep on the floor, she realises that it is down to her to take charge of him. Realising that he is hungry, she heads to the kitchen to make up some milk, but soon decides that the powder provided is all wrong for him- and after a little analysis on her computer, comes up with an ideal personalised milk formula to feed him with.
The next morning, Tenchi is surprised to find Washu cooking breakfast in the kitchen, with Taro in a baby sling on her back. Embarrassed, Washu pretends to be offhand and annoyed about looking after him, and quickly hands him back to Ryoko before returning to the lab.
Washu soon finds herself distracted, however, and after a few hours of unsuccessfully trying to get some work done, she decides to give up and take a break. Back in the main house, the girls have once again collapsed with exhaustion, leaving Taro playing with the milk powder by himself. It looks like Washu is going to have to take care of him again.
Fuelled by her past memories of a little blonde baby boy, Washu decides to take full-time care of Taro, leaving the other girls jealous and amazed as she expertly feeds him, cleans him, takes him out flying on Azaka, and even supervises the nappy washing. As Tenchi remarks, it is almost as if she has taken over as the baby’s mother, and even Taro himself starts calling her “mom”.
The next morning, Washu is preparing breakfast again, but even as she gets it ready, the doorbell rings. Tenchi’s aunt has arrived- it is time for Taro to go home.
Taro and Washu part a little unhappily, and Tenchi’s aunt thanks Washu for her hard work- amazing for one so young (or young-looking, anyway). As Taro and his family leave, Washu turns to Tenchi and admits that once, long ago, she too had a baby. The father was one of her Academy classmates, and she loved both her husband and son dearly. Unfortunately, because her husband was of noble blood, his family had them separated, and Washu lost her beloved family.
As Tenchi moves to comfort Washu, he is surprised to discover that she has transformed from her usual child-like appearance and taken the form of a full-grown woman. Washu tells Tenchi she wouldn’t mind having another child- as long as he is the father! After all, it seems unfair for Ryoko to be an only child- wouldn’t she like a little brother?
Neither Ryoko nor Ayeka are thrilled at the idea of Washu getting together with ‘their’ Tenchi, and pretty soon another fight breaks out as the two argue once more over which of them Tenchi belongs to. Whilst Mihoshi tries to break up the fight, Washu takes the opportunity to cuddle up to Tenchi. It seems no different from the usual Masaki house antics, except that someone is missing. Watching them from upstairs, Sasami sits quietly in her room. Sasami just hasn’t seemed her usual bright self lately- but what could possibly be the problem with Jurai’s young princess?